U.S. patent number 7,044,515 [Application Number 10/221,433] was granted by the patent office on 2006-05-16 for bumper beam with crush cans.
This patent grant is currently assigned to General Electric Company. Invention is credited to Dominic McMahon, Frank Mooijman, Srikanth M. Santhanam.
United States Patent |
7,044,515 |
Mooijman , et al. |
May 16, 2006 |
Bumper beam with crush cans
Abstract
A bumper assembly (10) for an automotive vehicle is described.
In an example embodiment, the assembly comprises a beam and a
fascia at least partially covering the beam. The beam comprises at
least one crush can (12).
Inventors: |
Mooijman; Frank (Halsteren,
NL), McMahon; Dominic (Bergen op Zoom, NL),
Santhanam; Srikanth M. (Windsor, CA) |
Assignee: |
General Electric Company
(Schenectady, NY)
|
Family
ID: |
21742837 |
Appl.
No.: |
10/221,433 |
Filed: |
September 12, 2001 |
PCT
Filed: |
September 12, 2001 |
PCT No.: |
PCT/US01/28583 |
371(c)(1),(2),(4) Date: |
September 10, 2002 |
PCT
Pub. No.: |
WO03/022640 |
PCT
Pub. Date: |
March 20, 2003 |
Prior Publication Data
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|
|
|
Document
Identifier |
Publication Date |
|
US 20030050619 A1 |
Mar 13, 2003 |
|
Current U.S.
Class: |
293/120; 293/102;
293/132; 293/133 |
Current CPC
Class: |
B60R
19/18 (20130101); B60R 2019/1846 (20130101); B60R
2019/1853 (20130101); B60R 2019/1866 (20130101); B60R
2019/1813 (20130101) |
Current International
Class: |
B60R
19/03 (20060101) |
Field of
Search: |
;293/102,120,132,133 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Coletta; Lori L.
Attorney, Agent or Firm: Armstrong Teasdale LLP
Claims
What is claimed is:
1. A bumper assembly comprising: a beam comprising: at least one
crush can; a first channel comprising an upper traverse wall, a
lower traverse wall, and an outer wall; a second channel comprising
an upper traverse wall, a lower traverse wall, and an outer wall;
and a back wall extending between said lower traverse wall of said
first channel and said upper traverse wall of said second channel;
said back wall, said lower traverse wall of said first channel, and
said upper traverse wall of said second channel defining a third
channel located between said first channel and said second channel;
and a fascia for covering at least a portion of said beam.
2. A bumper assembly according to claim 1 wherein said beam
comprises a thermoplastic.
3. A bumper assembly according to claim 1 wherein said beam
comprises a unitary elongated thermoplastic body.
4. A bumper assembly according to claim 1 wherein said crush can is
tunable.
5. A bumper assembly according to claim 1 wherein said beam further
comprises a frame.
6. A bumper assembly according to claim 1 wherein a first crush can
is configured to align with a first vehicle rail, and a second
crush can is configured to align with a second vehicle rail.
7. A bumper assembly according to claim 1 wherein said crush can
comprises a plurality of spaced walls, and wherein at least one of
wall spacing, wall angles, wall thickness, and wall material is
selectable.
8. An energy absorbing beam for a vehicle, said beam comprising a
frame and a body extending from said frame, said body comprising: a
first channel comprising an upper traverse wall, a lower traverse
wall, and an outer wall; a second channel comprising an upper
traverse wall, a lower traverse wall, and an outer wall; and a back
wall extending between said lower traverse wall of said first
channel and said upper traverse wall of said second channel; said
back wall, said lower traverse wall of said first channel, and said
upper traverse wall of said second channel defining a third channel
located between said first channel and said second channel; and at
least one crush can.
9. An energy absorbing beam according to claim 8 further comprising
a first vehicle rail attachment portion and a second vehicle rail
attachment portion, each of said vehicle rail attachment portions
configured to align and secure to a respective vehicle rail.
10. An energy absorbing beam according to claim 9 wherein said beam
comprises a thermoplastic.
11. An energy absorbing beam according to claim 9 wherein said beam
comprises a unitary elongated thermoplastic body.
12. An energy absorbing beam according to claim 9 wherein said
crush can is tunable.
13. An energy absorbing beam according to claim 9 wherein said
crush can comprises a plurality of spaced walls, and wherein at
least one of wall spacing, wall angles, wall thickness, and wall
material is selectable.
14. A molded plastic beam for a vehicle, said beam comprising: at
least one crush can; a first channel comprising an upper traverse
wall, a lower traverse wall, and an outer wall; a second channel
comprising an upper traverse wall, a lower traverse wall, and an
outer wall; and a back wall extending between said lower traverse
wall of said first channel and said upper traverse wall of said
second channel; said back wall, said lower traverse wall of said
first channel, and said upper traverse wall of said second channel
defining a third channel located between said first channel and
said second channel.
15. A beam according to claim 14 further comprising a frame and a
body extending from said frame, said body comprising a first and a
second flange, with a channel between said first and second
flanges.
16. A beam according to claim 14 wherein a first crush can is
configured to align with a first vehicle rail, and a second crush
can is configured to align with a second vehicle rail.
17. A beam according to claim 14 wherein said beam comprises a
thermoplastic.
18. A beam according to claim 14 wherein said beam comprises a
unitary elongated thermoplastic body.
19. A beam according to claim 14 wherein said crush can is
tunable.
20. A beam according to claim 14 wherein said crush can comprises a
plurality of spaced walls, and wherein at least one of wall
spacing, wall angles, wall thickness, and wall material is
selectable.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of International Application
No. PCT/US01/28583 filed Sep. 12, 2001.
BACKGROUND OF THE INVENTION
This invention relates generally to bumpers and, more particularly,
to bumper beams.
Bumpers typically extend widthwise across the front and rear of a
vehicle and are mounted to rails that extend in a lengthwise
direction. A typical bumper includes a steel beam or reinforcing
member attached to vehicle rails and covered by a fascia. Such
steel beams are heavy and typically deform, or buckle, on impact.
Energy from an impact therefore may be transferred to the vehicle
rails and result in additional damage to the vehicle.
Energy absorbing bumper systems attempt to reduce vehicle damage as
a result of a collision by managing impact energy and intrusion
while not exceeding a rail load limit of the vehicle. The
efficiency of a bumper system is defined as the amount of energy
absorbed over distance. A high efficiency bumper system absorbs
more energy over a shorter distance than a low efficiency bumper
system. High efficiency is achieved by building load quickly to
just under the rail load limit and maintaining that load constant
until the impact energy has been dissipated.
Some known energy absorbing bumper systems include a beam and an
energy absorber coupled to the beam. The energy absorber is
effective in absorbing energy from an impact. Separately
fabricating an energy absorber and assembling the energy absorber
to the beam increases both the fabrication and assembly costs of a
bumper assembly as compared to a simple steel beam bumper.
Other known energy absorbing bumper systems utilize a foam resin,
such as described in U.S. Pat. No. 4,762,352 and U.S. Pat. No.
4,941,701. Foam based systems typically have slow loading upon
impact, which results in a high displacement. Further, foams are
effective to a sixty or seventy percent compression, and beyond
that point, foams become incompressible so that the impact energy
is not fully absorbed. The remaining impact energy is absorbed
through deformation of a backup beam and/or vehicle structure.
Foams are also temperature sensitive so that displacement and
impact absorption behavior can change substantially with
temperature. Typically, as temperature is lowered, foam becomes
more rigid, resulting in higher loads. Conversely, as temperature
rises, foams become more compliant resulting in higher
displacements and possible vehicle damage.
Still other known bumper systems include crash cans. The crash cans
are separately fabricated and attached directly to a beam in
alignment with the vehicle rails. The crash cans absorb energy
during impact, e.g., an offset impact, and facilitate preventing
damage to the beam. Separately fabricating and attaching the crash
cans to the beam, however, increases bumper assembly costs and
complexity.
BRIEF SUMMARY OF THE INVENTION
In one aspect, a bumper assembly for an automotive vehicle is
provided. The bumper assembly comprises a beam and a fascia at
least partially covering the beam. The beam comprises at least one
crush can.
In another aspect, an energy absorbing beam for a bumper assembly
is provided. The beam comprises a frame and a body extending from
the frame. The body comprises a first transverse wall, a second
transverse wall spaced from the first wall, and at least one crush
can between the first and second walls.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective front view of a bumper beam;
FIG. 2 is a perspective rear view of a portion of the bumper beam
shown in FIG. 1;
FIG. 3 is a perspective front view of a portion of the bumper beam
shown in FIG. 1; and
FIGS. 4, 5, and 6 are cross-sectional views through line 4--4 in
FIG. 3 and showing different crush can wall configurations.
DETAILED DESCRIPTION OF THE INVENTION
A thermoplastic bumper beam that includes tunable crush cans is
described below in detail. The term tunable, as used herein, means
that characteristics, e.g., wall angles, of the crush cans can be
selected to provide a desired operating result, as described below
in more detail. The crush cans are sometimes described herein as
being integral with the beam, which means that the crush cans are
formed as a component of, and not separately from, the beam, which
results in a one-piece unitary structure for the beam. The term
integral also includes constructions in which the beam is molded in
segments, and then the segments are secured together, e.g.,
welded.
Combining the crush cans with the beam results in a bumper system
that absorbs energy without necessitating a separate energy
absorber attached to the beam. For example, impact forces during
low speed impacts are maintained just below a predetermined level
by deforming the beam until the kinetic energy of the impact event
has been absorbed. When the low speed impact is over, the beam
returns substantially to its original shape and retains sufficient
integrity to withstand subsequent impacts.
Further, combining the efficient energy absorbing properties of a
thermoplastic beam with the integrated crush cans is believed to
provide improved impact absorbing performance over traditional
metal beams. In addition, the thermoplastic beam with integrated
crush cans is believed to provide more efficient impact absorption
than thermoplastic beams that do not include crush cans.
The bumper beam can be fabricated from one of many plastic
materials including, for example, Xenoy.RTM. material which is
commercially available from General Electric Company, Pittsfield,
Mass. The beam is not limited to practice with such material and
other materials can be used.
More specifically, the characteristics of the material utilized to
form the beam include high toughness/ductility, thermally stable,
high energy absorption capacity, a good modulus-to-elongation ratio
and recyclability. While the beam may be molded in segments, the
beam also can be of unitary construction made from a tough plastic
material. An example material for the beam is Xenoy material, as
referenced above. Of course, other engineered thermoplastic resins
can be used. Typical engineering thermoplastic resins include, but
are not limited to, acrylonitrile-butadiene-styrene (ABS),
polycarbonate, polycarbonate/ABS blend, a
copolycarbonate-polyester, acrylic-styrene-acrylonitrile (ASA),
acrylonitrile-(ethylene-polypropylene diamine modified)-styrene
(AES), phenylene ether resins, blends of polyphenylene
ether/polyamide (NORYL GTX.RTM. from General Electric Company),
blends of polycarbonate/PET/PBT, polybutylene terephthalate and
impact modifier (XENOY.RTM. resin from General Electric Company),
polyamides, phenylene sulfide resins, polyvinyl chloride PVC, high
impact polystyrene (HIPS), low/high density polyethylene (l/hdpe),
polypropylene (pp) and thermoplastic olefins (tpo). The beam also
could, for example be fabricated (e.g., compression molded) from a
glass mat thermoplastic (GMT), such as Azdel.RTM. material
(commercially available from Azdel, Inc., Shelby, N.C. and
described in U.S. Pat. No. 5,643,989).
Referring now specifically to the drawings, FIGS. 1 and 2 are a
front perspective view of a bumper 10 including integral tunable
crush cans 12 and a rear view of a portion of bumper 10,
respectively. A fascia (not shown) ordinarily would be secured to
beam 10 and typically is formed from a thermoplastic material which
is amenable to finishing utilizing conventional vehicle painting
and/or coating techniques. The fascia envelopes beam 10 such that
beam 10 is not visible once attached to the vehicle.
Beam 10 has a generally rectangular cross sectional shape and
includes a frame 14. A body 16 that extends from frame 14 includes
first and second longitudinally extending flanges 18 and 20.
Flanges 18 and 20 define a channel 22 that also extends
longitudinally. A plurality of reinforcing and stiffening ribs 24
are positioned between flanges 18 and 20 in channel 22, and also on
exterior surfaces 26 and 28 of flanges 18 and 20.
Beam 10 also includes vehicle attachment portions 30, 32, and
includes openings 34 for securing beam 10 to the frame rails of the
vehicle. Reinforcing members 36 extend from body 16 to attachment
portion 32. Crush cans 12 generally are located in alignment with
the vehicle rails when bumper 10 is secured to a vehicle. By
positioning crush cans 12 in alignment with the vehicle rails, such
crush cans operate to facilitate reducing damage to the vehicle
during an impact.
Referring to FIG. 3, which is a perspective front view of a portion
of bumper 10, crush can 12 includes a plurality of walls 50, 52,
54. Also, and referring to FIGS. 4, 5 and 6, which are cross
sectional views through line 4--4 in FIG. 3 and illustrate
alternative crush angles A, B, C, varying crush angles A, B, C
results in different stiffness and impact characteristics. For
example, by changing walls 50, 52, 54 to be more upright, crush can
12 is more stiff. Also, positioning walls 50, 52, 54 closer
together results in increasing the stiffness of crush can 12. In
addition, spacing of ribs 24 can be altered, i.e., beam 10 becomes
more stiff as ribs 24 are spaced closer together.
By varying at least the wall angles A, B, C, the spacing of walls
50, 52, 54, and the spacing of ribs 24, crush can 12 is tunable to
provide a desired stiffness. Since vehicles have different weights
and operating applications (e.g., non-commercial passenger vehicle,
commercial passenger vehicle, light truck), bumper 10 can be tuned
for a particular vehicle weight and application.
Of course, other variables can be used to for tuning crush cans 12.
For example, crush can 12 can also be tailored for specific
applications by varying the wall thickness of walls 50, 52, 54. For
example, the nominal thickness of the walls may broadly range from
about 1.75 mm to about 3.0 mm. More specifically, for certain low
impact applications the nominal wall thickness may generally range
from about 1.75 mm to about 2.0 mm and for other applications the
walls would more likely be in the range of about 2.5 mm to 3.0
mm.
Another aspect in appropriately tuning crush cans 12 is the
selection of the thermoplastic resin to be employed. The resin
employed may be a low modulus, medium modulus or high modulus
material as needed. By carefully considering each of these
variables, crush cans 12 can meet the desired energy impact
objectives.
As explained above, integrating crush cans with an injection molded
thermoplastic beam is believed to provide enhanced energy
absorption efficiency over steel beams and simple thermoplastic
beams. Enhanced impact performance translates to reduced costs of
repair for low speed "fender benders" and reduced vehicle damage
during higher speed collisions. Further, since a separate energy
absorber is not utilized, cost savings also are believed to be
achieved with such a bumper beam configuration. The combination of
the thermoplastic beam and the tunable crush cans provides an
efficient, fast loading and controlled impact event.
While the invention has been described in terms of various specific
embodiments, those skilled in the art will recognize that the
invention can be practiced with modification within the spirit and
scope of the claims.
* * * * *